Also you should be aware that some of the arduino clones, derivatives, and counterfeit replicas might be using fake atmega IC's that works similar to the original ones but they are not original and sometimes they have problems with simple calculations that screw all your project making it non-workable.But for easy things, they do the job and also with more complex things they do the job (or not) it depends on their mood

Can you point to an actual example of that?Really bad counterfeits probably won't work at all, or have a different chip than advertised (lately there have been several instances of people ordering Atmega328-based boards, and getting a board with an ATmega8.) And there are boards with counterfeit USB chips (prolific being widely counterfeited, in particular) that may have issues with USB drivers. But I've never heard of a "partially functional" counterfeit giving bad results to calculations...

Can you point to an actual example of that?Really bad counterfeits probably won't work at all, or have a different chip than advertised (lately there have been several instances of people ordering Atmega328-based boards, and getting a board with an ATmega8.) And there are boards with counterfeit USB chips (prolific being widely counterfeited, in particular) that may have issues with USB drivers. But I've never heard of a "partially functional" counterfeit giving bad results to calculations...

If you are working with a SD card, sometimes when you want to do something, it simple doesn't do it. In that case i have to flash the bootloader again.For example, saving values inside variables, comparing values from one variable to another, it doesn't work.The magic about the counterfeits is that if you flash the bootloader, they start to work again (well at least it's how i've been solving mines)